Study on the adhesion and tribological behavior of PVD TiAlN coatings with a multi-scale textured substrate surface

In this paper, we investigated the effects of multi-scale textures on improving the adhesion of PVD TiAlN coating-carbide substrate composites, which is crucial for tribological applications. The substrate pre-treatments were conducted using a nanosecond laser and a femtosecond laser to produce three types of surface textures: (i) micro-scale textures, (ii) nano-scale textures and (iii) micro/nano-scale textures. Characterization tests such as variable depth scratch tests and ball-on-disk wear tests were performed to evaluate the coating adhesiveness as well as the tribological behavior of the PVD TiAlN coatings deposited on the multi-scale textured substrates. The results revealed that the adhesion of three textured TiAlN coatings was greatly improved over that of the untextured one and that anti-adhesive wear properties of TiAlN coatings against AISI 316 stainless steel were significantly improved by using laser substrate pre-treatment. Moreover, the type of surface textures had a profound effect on the adhesive strength and tribological properties of the pre-treated samples. In the experiment, the micro/nano-scale texture was the most effective in providing a mechanical locking of the coatings on the substrate, a matching chemical property between substrate and coating materials, and a high active substrate surface, thus increasing the critical load of the coatings.